Just to reconfirm HiFiMAN's policy of not selling just the headband, here's my recent exchange with Mark in customer service:
Is it possible to buy just the headband for the HE-560 (or HE-400i; should be the same, yes?)? The plastic yoke on mine snapped and is currently held together with Super glue and electrical tape. I'm not confident that solution will hold up over time.
If I can buy just the headband, how much is it? I've read in the past that they were $50.
"Hi there, we do offer a headband replacement service that is indeed US$50 plus US$30 for the return shipping to you. We dont however make the parts available to the public, we would have to carry out the actual replacement for you. Would that be okay with you?
"No thanks. I'm quite capable of doing the job myself, and don't want to be without my headphones. I guess if it breaks and I can't fix it adequately, I'll look to a different headphone manufacturer. Feel free to pass that up the chain to Fang Bian.
an owner of three different HiFiMAN headphones"
And I'm quite sincere. Wish I'd found this thread back in the day. OTOH, the Audeze pads are the best I've tried (and I've tried a lot of different pads), but it took some doing to get the Vegans to fit on my HE-560s. No such problem with the lambskin on the HE-500s, so I'm not sure I would go with the new headband.
That's a shame, then again, I didn't think the mod would take off the way it has!